Re-purposing blood-pressure medications could reduce prostate cancer recurrence rate

Alpha blockers (blood pressure medication) may reduce the risk of prostate cancer recurrence and delay the time to chemical relapse a Griffith University study published in the Nature published journal, Scientific Reports has found.

Associate Professor Shai Dukie and his team (Professor David Christie, Briohny Spencer and Jordan Hart) from the School of Pharmacy and Pharmacology and collaborators from the Centre for Urology Research, Bond University analysed data from several thousand patients with adenocarcinoma of the prostate who received radiotherapy at a Gold Coast cancer care facility (2000-2017).

“Our research showed that the alpha blocker prazosin, at clinically relevant doses is able to significantly reduce the risk of prostate cancer recurrence as well as delay time to biochemical relapse in prostate cancer patients following radiotherapy,’’ Associate Professor Dukie said.

Patient groups included a control group and men receiving tamsulosin and prazosin at the time of radiotherapy.

The researchers found that prazosin significantly reduced the number of patients who experienced biochemical relapse at both the two and five-year points when compared to the control and tamsulosin groups. In contrast, another alpha blocker, tamsulosin was found to have no significant effect on both two and five-year relapse rates or recurrence free survival.

“The study showed that prazosin patients have a 3.9 times lower relative risk of biochemical relapse when compared to the control group,’’ Associate Professor Dukie said.

“Interpretation of the risk difference indicated 257 fewer prostate cancer cases would have developed per 1000 treated men, in this case 38 additional cases of cancer recurrence could have been expected had the patients not received prazosin.”

Most forms of prostate cancer are extremely treatable with a five-year survival rate of 95%, however it is estimated that between 20—50% of patients will experience biochemical relapse within 10 years depending on treatment choice.

Currently, although several treatment options exist such as radiotherapy, radical prostatectomy, androgen deprivation and chemotherapy, some of these are invasive and associated with a number of adverse effects as well as the development of treatment resistance.

“Therefore, there is an urgent need to identify effective primary or adjunct treatment options and alpha blockers may represent one of these options,’’ Associate Professor Dukie said.

“The added advantage of these agents is that they have been used clinically for many years so we have good safety data on them.

“The next step in our research is a clinical trial which we hope to start soon with one of our graduates and clinical trial pharmacist (Liam King), leading as part of his PhD at Griffith.”

Prostate cancer is the fourth most prevalent cancer worldwide and the most common solid tumour among males. In Australia, an estimated 17,729 new cases of prostate cancer are diagnosed each year and it is the second leading cause of cancer related death among Australian men.

Approximately 80% of new diagnoses are clinically localised with a five-year survival rate of approximately 95%, however, the cancer will eventually transition to castrate resistant disease. Following this transition, the disease is ultimately incurable with a median survival of 14 months.